Sewage Treatment System

Abstract

A sewage treatment system is provided that suppresses the generation of hydrogen sulfide in a pump tank and in a sewer pipe downstream of the pump tank. [Solution] The sewage treatment system includes a microbial material manufacturing device for manufacturing microbial material to reduce the generation of hydrogen sulfide, a microbial material supplying device for supplying the microbial material from the microbial material manufacturing device to the sewage in a pump tank, and a blower for sending air into the sewage in the pump tank. The microbial material supplying device includes a sewage supplying device for supplying the sewage in the pump tank to the microbial material supplying device. The microbial material is dissolved in the sewage from the sewage supplying device to produce a microbial material mixture, and this microbial material mixture is supplied to the sewage in the pump tank. The microbial material supplied to the sewage in the pump tank and the air sent into the sewage in the pump tank suppress the generation of hydrogen sulfide in the pump tank and in the sewer pipe downstream of the pump tank.

Description

[Technical Field]

[0001] The present invention relates to a sewage treatment system, and more particularly to a sewage treatment system that can reduce the generation of hydrogen sulfide in pump tanks such as relay pumping stations and downstream sewer pipes. [Background technology]

[0002] Sewage flows into sewer pipes constantly from homes, factories, and businesses. This sewage carries with it human intestinal bacteria, organic matter, and microorganisms (mainly bacteria) from factories. While sewage absorbs oxygen from the air as it flows down the sewer pipes, the microorganisms' oxygen uptake generally creates anoxic conditions. As a result, anaerobic sulfate-reducing bacteria become more active, using sulfate to decompose organic matter. This process generates hydrogen sulfide gas, which not only contributes to the foul odor of sewage but also poses a toxic risk to workers entering through manholes. Furthermore, when this hydrogen sulfide gas dissolves in the water film on the walls of pump tanks and sewer pipes, sulfuric acid-producing bacteria multiply and utilize the biofilm to produce sulfuric acid, which corrodes, deteriorates, and collapses the cement walls of pump tanks and sewer pipes. Extending the lifespan of concrete pipes, which are the basis of sewerage systems, is an extremely important issue in maintaining and managing urban infrastructure.

[0003] To solve this problem, Japanese Patent Publication No. 3-55199 proposes a system in which an oxygenator (oxygen addition) is installed midway through a sewer pipe, and the sludge in the sewage flowing down the sewer pipe is taken into this oxygenator, oxygen is added to it, and this is then returned to the sewage flowing down the sewer pipe, thereby maintaining a positive dissolved oxygen concentration in the sewage.

[0004] The device described in the above patent publication can certainly maintain a positive dissolved oxygen concentration in the sewage in the sewer pipes, but that is all it can do.

[0005] Therefore, the applicant has gone one step further and filed a patent application for a sewage treatment system that can maintain a positive dissolved oxygen concentration in the sewage flowing down the sewer pipe downstream of the relay pumping station, and can change the microbial state on the inner wall of the sewer pipe to prevent corrosion of the sewer pipe.

[0006] The sewage treatment system according to the applicant's aforementioned patent application is described as "a sewage treatment system comprising an intermediate pumping station for sewage discharged from homes, factories, businesses, etc., a primary sedimentation tank, a biological treatment tank, and a final sedimentation tank, which receives sewage from the intermediate pumping station via a sewerage pipe and treats it, and which comprises dehydration means connected to the primary sedimentation tank and / or the final sedimentation tank, which receives and dehydrates the settled sludge from the primary sedimentation tank and / or excess sludge from the final sedimentation tank, and which supplies oxygen to the dehydrated sludge from the dehydration means while maintaining the temperature at 60°C to 110°C, causing aerobic fermentation by gram-positive aerobic microorganisms in the dehydrated sludge, thereby decomposing and killing gram-negative anaerobic microorganisms and also preventing the growth of bacteria that grow after this aerobic fermentation." a microbial material production device that produces a microbial material containing spores of aerobic microorganisms produced by the microbial material production device; a water supply means for supplying water from any one of the systems of the sewage treatment system to a microbial activation device described below; a microbial activation device that receives the microbial material from the microbial material production device and supplies water from the water supply means to the microbial material while maintaining the temperature of the water in the range of 10°C to 40°C and the oxygen concentration in the range of 1 to 10 mg / L to germinate and activate the spores of the microbial material; and an oxygen supply means that supplies oxygen to sewage at any one of the relay pumping stations, and sends sewage containing the activated microbial material and the oxygen supplied from the oxygen supply means from the relay pumping station to the sewage treatment facility. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 3-55199 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a sewage treatment system that utilizes the hydrogen sulfide suppression effect of microbial materials, which were obtained as a result of the inventors' extensive research. [Means for solving the problem]

[0009] The above object of the present invention is achieved by a sewage treatment system according to the present invention having the following configurations (1) to (10). (1) A sewage treatment system comprising a pumping station that is a relay pumping station and / or a manhole pumping station, which is provided with a pump tank in which a lifting pump is disposed, and a sewage treatment facility that receives and treats sewage from the pumping station, A microbial material manufacturing device that processes sludge generated in a sewage treatment system to manufacture a microbial material containing aerobic microorganisms; To reduce the generation of hydrogen sulfide , containing aerobic microorganisms Contains microbial materials; With the aerobic microbial community activated, a microbial material supplying device for supplying the sewage in the pump tank; and Air is sent to the sewage in the pump tank, For further activating the aerobic microbial population supplied to the sewage in the pump tank It is equipped with a blower, The microbial material supply device is provided in the pump tank. The aerobic microorganisms were further activated. The apparatus is provided with a sewage supply device for supplying sewage to the microbial material supply device, and the microbial material is Furthermore, activated aerobic microorganisms were mixed in. Dissolved in sewage and pumped from the pump tank Also contains aerobic microorganisms A microbial material mixture is prepared, and the microbial material mixture is supplied to the sewage in the pump tank. The generation of hydrogen sulfide in the pump tank and the sewer pipe downstream of the pump tank is suppressed by the microbial material supplied to the sewage in the pump tank and the air sent to the sewage in the pump tank. A sewage treatment system characterized by: (2) The sewage treatment system of (1) has a sewage supply pipeline between the pump tank and the water supply device in order to supply sewage containing microbial materials in the pump tank to the microbial material supply device. (3) The microbial material supply device is provided with a first operation control device for controlling its operation, On the other hand, the pump tank is provided with a second operation control device for instructing the operation of the lifting pump, and when the water level in the pump tank reaches a predetermined high level, this second operation control device starts the operation of the lifting pump, and when the water level reaches a predetermined low level, stops the operation of the lifting pump, The first operation control device controls the microbial material supply device when the water level reaches a predetermined low level. Operation The sewage treatment system of (1) is configured to add the microbial material mixture to the sewage in the pump tank. (4) The sewage treatment system according to (3), wherein a water level meter is provided to detect the predetermined low level and the predetermined high level. (5) The sewage treatment system according to (1), wherein the microbial material supplying device further injects microbial materials into the sewage in the sewer pipe downstream of the pump tank. (6) The sewage treatment system according to (1) above, further comprising a supply pipe for supplying the microbial material mixture from the microbial material supply device to the sewage in the pump tank. (7) The sewage treatment system according to (1), wherein the microbial material is a decomposition product of sludge generated in the sewage treatment facility by hyperthermophilic aerobic microorganisms. (8) The sewage treatment system according to (7), wherein the decomposition product is an aerobic fermentation product. (9) The sewage treatment system according to (7), wherein the decomposed product is fertilizer, compost or soil conditioner. (10) A sewage treatment system further comprising a microbial material production device for producing the microbial material according to any one of (7) to (9) above. [Effects of the Invention]

[0010] In the sewage treatment system of the present invention, the generation of hydrogen sulfide can be reduced by supplying the microbial material mixture and air to the sewage in the pump tank. Furthermore, since the microbial material-mixed sewage with an improved oxygen concentration flows from the pump tank to the sewer pipe downstream of the pump tank, the generation of hydrogen sulfide in the sewer pipe can also be reduced. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a conceptual diagram showing the configuration of a sewage treatment system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the state of the inner wall of a sewer pipe on which a biofilm has formed. DETAILED DESCRIPTION OF THE INVENTION

[0012] A sewage treatment system 10 according to an embodiment of the present invention will be described below with reference to the accompanying drawings. Note that although the present invention covers both relay pumping stations and manhole pumping stations as pumping stations provided in a sewage treatment system, the following description will focus on relay pumping stations as a representative example.

[0013] The sewage treatment system 10 includes a relay pumping station 20 for sewage discharged from homes, factories, businesses, etc., and a pump tank 22 into which the sewage to be relayed flows. The pump tank 22 is connected to an upstream sewer pipe 30 for sewage discharged from homes, factories, businesses, etc., and a downstream sewer pipe 32 for sewage heading to a sewage treatment facility (not shown) at its upstream side and a downstream sewer pipe 32 for sewage heading to a sewage treatment facility (not shown) at its downstream side. A pump P is located at the bottom of the pump tank 22 to pump the sewage stored in the pump tank 22 and send it to the downstream sewer pipe 32. The pump tank 22 is also equipped with a blower 24 for supplying oxygen (air) to the stored sewage. The oxygen (air) supplied by the blower 24 increases the amount of dissolved oxygen in the stored sewage, further activating the microorganisms in the sewage in the pump tank 22, which further activates the microbial populations in the microbial material supplied to the pump tank 22, as described below.

[0014] As shown in Figure 2, a biofilm BF, a community of microorganisms, forms on the inner wall of the downstream sewer pipe 32 in areas that are constantly in contact with the sewage flow, especially in areas where the sewage flow comes into contact with the deeper water (a biofilm BF is also formed on the inner wall of the pump tank 22), and this becomes the source of hydrogen sulfide. The sewage treatment system 10 of the present invention is equipped with a microbial material supply device 40, and it is expected that the generation of hydrogen sulfide will be reduced by the effect of the microbial material, which reduces and / or prevents the formation of the biofilm, using a group of microorganisms from this microbial material supply device 40.

[0015] The microbial material supply device 40 is installed, for example, in a sewage treatment system 10, and receives microbial material from a microbial material production device 42 that processes sludge generated in the system and produces microbial material containing useful mainly aerobic microorganisms, and activates (germinates) the microorganisms (mainly in the form of spores) contained in the microbial material and supplies it.

[0016] The microbial material production device 42 produces a decomposition product, i.e., a microbial material containing beneficial aerobic and anaerobic microorganism spores, while minimizing harmful gram-negative anaerobic and facultative anaerobic microorganisms. The decomposition process generates heat, which decomposes and kills gram-negative anaerobic microorganisms. The decomposition process also depletes the moisture and nutrients in the dehydrated sludge, causing the aerobic and facultative anaerobic microorganisms in the raw material to spore. This microbial material contains the hyperthermophilic aerobic microorganisms that functioned in the decomposition process. That is, the microbial material is, for example, a decomposition product of sludge generated in a sewage treatment facility, which is decomposed by hyperthermophilic aerobic microorganisms. The decomposition product is, for example, an aerobic fermentation product. Specific examples of the decomposition product include fertilizer, compost, and soil conditioner. Here, in this specification, the term "hyperthermophilic aerobic microorganisms" refers to microorganisms that thrive at temperatures of 80°C or higher, which is higher than the commonly known definition of hyperthermophilic aerobic microorganisms, 60°C. Examples of such microorganisms include those in the phylum Bacillota that thrive at temperatures of 80°C or higher, and those in the phylum Actinomycetota that thrive at temperatures of 80°C or higher. In addition, the beneficial aerobic microorganisms and facultative anaerobic microorganisms include microorganisms that grow at room temperature, such as microorganisms of the phylum Bacillota, class Bacilli, and microorganisms of the phylum Actinomycetota, class Actinobacteria.

[0017] As described above, the microbial material supply device 40 is designed to supply sewage from a sewage supply device 44 via a pipeline 45 and oxygen (usually as air) from an oxygen supply device 46 in order to activate the microbial population in the microbial material. The sewage supplied by the sewage supply device 44 is preferably the sewage in the pump tank. This sewage contains nutrients necessary to activate the microbial population in the microbial material, and also contains the microbial material supplied previously and before, allowing the microbial material to function efficiently.

[0018] In this microbial material supplying device 40, the microbial material and the sewage are mixed to prepare a microbial material mixture. The amount of the microbial material to be supplied to the microbial material supplying device 40 is preferably about 10 g per 1 m 3 of water in the microbial material supplying device 40 . The amount of microorganism-containing water supplied from the microbial material supply device 40 to the pump tank is preferably about 4% of the pump tank volume at a predetermined height, which will be described later.

[0019] The microbial material supplying device 40 is provided with a first operation control device 48, which controls the ON / OFF of the supply of the microbial material mixture, that is, the operation of the device. On the other hand, the pump tank 22 is provided with a second operation control device 50 for instructing the operation of the pump P.

[0020] A main control device 60 is connected to the first operation control device 48 and the second operation control device 50. This main control device 60 controls the supply of the microbial material mixture from the microbial material supply device 40 by the first operation control device 48 in accordance with the sewage water level in the pump tank 22, while controlling the operation and stop of the pump P by the second operation control device 50.

[0021] The phrase "according to the sewage water level" means, for example, when the water level reaches a predetermined high level and when it reaches a predetermined low level. When the water level reaches the predetermined high level, the main control device 60 causes the second operation control device 50 to operate the pump P to pump the sewage stored in the pump tank 22 and supply it to the downstream sewer pipe 32. On the other hand, when the water level reaches the predetermined low level, the main control device 60 causes the first operation control device 48 to operate the microbial material supply device 40 to supply the activated microbial material mixture into the pump tank 22, in other words, to the sewage stored in the pump tank 22.

[0022] For this reason, the pump tank 22 is provided with a first water level gauge 52 that detects the predetermined high level of the sewage and outputs a high level signal S1, and a second water level gauge 54 that detects the predetermined low level of the sewage and outputs a low level signal S2.

[0023] In the embodiment described above, the microbial material supply device is described as being in a form in which a microbial material mixture is injected into the sewage in the pump tank, but the microbial material supply device may also be configured to inject a microbial material mixture into the sewage in the upstream sewer pipe 30.

[0024] Working Example (Experimental Example) Next, an example and an experimental example of the operation of the sewage treatment system having the above-described configuration will be described. In the following examples and experimental examples, biofilms were collected from the inner walls of sewer pipes in an actual environment where hydrogen sulfide was being generated, and this biofilm was mixed with sewage to prepare a biofilm suspension. This was then anaerobically cultured under constant temperature conditions to experimentally prepare an experimental system (control group) in which hydrogen sulfide was generated, and microbial materials were added to these conditions. First, actual sewage was collected at the inlet of a relay pump station in one of the sewer systems in H City, Saitama Prefecture, and at the same time, biofilms attached to the sewer pipes were collected, and comparative samples and example samples were prepared under the following conditions. 1. Preparation of biofilm suspension The biofilm collected as described above was thoroughly stirred to prepare a biofilm suspension. 2. Preparation of Experimental Samples An experimental sample was prepared by adding 1 ml of the biofilm suspension prepared in 1 above to 400 ml of the actual sewage collected as described above. 3. Preparation of microbial materials The sludge generated in the biological treatment tank of the sewage treatment facility in the sewerage system was dehydrated and decomposed in the microbial material production device 42 using hyperthermophilic aerobic microorganisms such as microorganisms of the phylum Bacillota and Actinomycetota to produce a microbial material. In the experiment, this microbial material was used as is. That is, a microbial material supply device (activation device) for activating beneficial microbial populations in the microbial material was not used, and the microbial material was used as is. The experimental time was set to be sufficient for the microbial populations in the microbial material to germinate, so the activation device was omitted. The main microorganisms confirmed in this microbial material were hyperthermophilic aerobic microorganisms that functioned in the decomposition of sludge (raw material) in the production of this microbial material, as well as microorganisms of the classes Bacilli and Actomycetes, which are believed to be beneficial microorganisms that prevent or reduce the generation of hydrogen sulfide, which is the effect of the present invention. The prevention or reduction of hydrogen sulfide generation, which is the effect of the present invention, is believed to be achieved by at least one of these beneficial microorganisms. 4. Experimental specifications Comparative Example: A comparative example was prepared by adding no microbial material to the experimental sample. Example: 10% (40 g) of microbial material was added to 400 ml of the above-mentioned experimental sample to prepare an example sample.

[0025] Experimental environment The comparative example and example samples were placed in two sealed containers, each with a volume of approximately 570 ml, with 400 ml of each. The air in the containers was replaced with nitrogen gas, and the containers were left standing at a temperature of 25 to 26°C. After 7 days, the hydrogen sulfide concentration in the containers was measured.

[0026] Experimental results In the comparative example, about 115 ppm of hydrogen sulfide was detected. On the other hand, in the example, the hydrogen sulfide concentration was less than 10 ppm, which was significantly lower than that in the comparative example. As described above, when the sewage treatment system of the present invention is applied to a pump tank in an actual sewage system, it is expected that the generation of hydrogen sulfide will be reduced. Although the function of the ultra-high temperature aerobic microorganisms in the microbial material in preventing or reducing the generation of hydrogen sulfide, which is the effect of the present invention, could not be confirmed, they are present in the sewage in the pump tank and, as a result, in the sludge that serves as the raw material for the microbial material, and contribute to the production of the next microbial material by the microbial material production device 42. [Explanation of symbols]

[0027] 10 Sewage Treatment System 20 Relay Pump Station 22 Pump Tank 24 Blois 30 Upstream sewer pipe 32 Downstream sewer pipe 40 Microbial material supply device 42 Microbial material manufacturing equipment 44 Sewage supply equipment 45 Conduit 46 Oxygen supply device 48 First operation control device 50 Second operation control device 52 1st water level gauge 54 2nd water level gauge 60 Main control device P pump

Claims

1. A sewage treatment system including a pumping station that is a relay pumping station and / or a manhole pumping station, which includes a pump tank in which a lifting pump is disposed, and sewage treatment equipment that receives and treats sewage from the pumping station, A microbial material manufacturing device that processes sludge generated in a sewage treatment system to manufacture a microbial material containing aerobic microorganisms; a microbial material supplying device for storing the microbial material containing aerobic microorganisms for reducing the generation of hydrogen sulfide and supplying the aerobic microorganisms in an activated state to the sewage in the pump tank; and a blower for blowing air into the sewage in the pump tank to further activate the aerobic microorganisms supplied to the sewage in the pump tank; The microbial material supplying device is provided with a sewage supplying device for supplying the sewage in the pump tank that has been further activated and that has been mixed with the aerobic microorganisms to the microbial material supplying device, and the microbial material is dissolved in the sewage that has been further activated and that has been mixed with the aerobic microorganisms to prepare a microbial material mixture that also contains the aerobic microorganisms from the pump tank, and this microbial material mixture is supplied to the sewage in the pump tank. The generation of hydrogen sulfide in the pump tank and the sewer pipe downstream of the pump tank is suppressed by the microbial material supplied to the sewage in the pump tank and the air sent to the sewage in the pump tank. A sewage treatment system characterized by:

2. The sewage treatment system of claim 1, wherein a sewage supply pipe is provided between the pump tank and the sewage supply device so that the sewage containing microbial materials in the pump tank can be supplied to the microbial material supply device.

3. The microbial material supply device is provided with a first operation control device for controlling its operation, On the other hand, the pump tank is provided with a second operation control device for instructing the operation of the lifting pump, and when the water level in the pump tank reaches a predetermined high level, this second operation control device starts the operation of the lifting pump, and when the water level reaches a predetermined low level, stops the operation of the lifting pump, 2. The sewage treatment system of claim 1, wherein the first operation control device is configured to operate the microbial material supply device to inject the microbial material mixture into the sewage in the pump tank when the water level reaches a predetermined low level.

4. 4. The sewage treatment system of claim 3, further comprising a water level indicator for detecting said predetermined low level and said predetermined high level.

5. 2. The sewage treatment system according to claim 1, wherein said microbial material supplying device further injects microbial materials into the sewage in the sewer pipe downstream of said pump tank.

6. 2. The sewage treatment system according to claim 1, further comprising a supply pipe for supplying the microbial material mixture from said microbial material supply device to the sewage in said pump tank.

7. 2. The sewage treatment system according to claim 1, wherein the microbial material is a decomposition product of sludge generated in the sewage treatment facility by hyperthermophilic aerobic microorganisms.

8. 8. The sewage treatment system according to claim 7, wherein the decomposition product is an aerobic fermentation product.

9. 8. The sewage treatment system according to claim 7, wherein the decomposed product is a fertilizer, compost or soil conditioner.

10. A sewage treatment system further comprising a microbial material production device for producing the microbial material according to any one of claims 7 to 9.

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